<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>弹性盒</title>
    <!-- 弹性盒 特别适合移动端布局 -->

    <style>
        .box{
            width: 500px;
            height: 500px;
            border: 2px solid black;
            margin: 100px auto;

            /* 盒子显示为弹性盒子 
                影响
                1、子元素默认横向排列
                2、父盒子加上弹性 行内元素边为块元素
                3、只有一个元素的时候  margin: auto;自动居中
                
            */
            display: flex;
        }

        .box span{
            width: 100px;
            height: 100px;
            border: 1px darkcyan dashed;
            text-align: center;
            margin: auto;
            

        }


    </style>


</head>
<body>
    
    
    <div class="box">

        <span>111</span>
        <!-- <span>222</span>
        <span>333</span>
        <span>444</span>
        <span>555</span>
        <span>555</span>
        <span>555</span> -->

    </div>

</body>
</html>